1. Field of the Invention This device relates generally to a recording and/or reproducing apparatus for magnetic disks which include polymeric sheets stretched over disk-like base plates.
2. Description of the Prior Art
A relatively new medium for mass data storage is known as a stretched surface recording (SSR) disk wherein at least one thin polymeric film is stretched across and attached to a circular base plate which is inflexible compared to the film.
A recording and/or reproducing apparatus (drive) for such a disk includes a drive motor for rotating the disk and a transfer mechanism for moving the recording head, all secured to a chassis. When the disk is mounted on the drive and driven by the drive motor, the head in proximity to the magnetic sheet is moved in the radial direction of the disk to transfer information to and from the disk.
However, when data transfer is performed by the above-mentioned drive, tracking errors are often produced due to changes of temperature.
The base plate of the magnetic disk is molded from synthetic resin, whereas the chassis of the drive is made of metal, so that expansion and contraction of the chassis due to temperature or humidity changes are smaller than those of the base plate. Hence, positional errors are produced between the track on the magnetic sheet which is secured to the base plate, and the head held by the transfer mechanism which is secured to the chassis.
As the tracks of the magnetic disk tend to become denser so as to enable the disk to perform high density recording, a complex servo-mechanism will become necessary to overcome tracking errors produced by environmental changes.